Thread controller for sewing machines



Oct. 25, 1932. T

THREAD CONTROLLER FOR SEWING MACHINES Filed July 22, 1930 5 Sheets-Sheet 1 W MZ wouwus Oct. 25, 1932. TZ 1,884,028

THREAD CONTROLLER FOR SEWING MACHINES Filed July 22. 1930 3 Sheets$heet 2 .Z 0 I J Oct. 25, 1932. LUTZ THREAD CONTROLLER FOR SEWING MACHINES Filed July 22, 1930 I5 Sheets-Sheet 5 Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE FRIEDRICH LUTZ, F STUTTGART, GERMANY, ASSIGNOR TO UNION SPECIAL MASOHINEN- FABRIK, G. M. 13. IL, OF STUTTGART, GERMANY THREAD CONTROLLER FOR SEWING MACHINES Application filed July .22, 1930, Serial No. 469,766, and in Germany July 3-1, 1929.

The invention relates to new and useful improvements in thread controllers for sewing machines, and more particularly to a thread controller for the looper of a sewing machine. 7 7

An object of the invention is to provide a thread controller for the looper thread which takes up the looper thread on the first part of the backward movement of the looper and then gives slack to the looper thread under control so that the looper may be moved to the rear end of its stroke.

A further object of the invention is to provide a looper thread controller of the above type wherein the moving parts are directly associated with the looper operating mechanism beneath the work support.

A still further object of the invention is to provide a thread controller of the above type wherein the active take-up member of the thread controller is-adjustably mounted on the operating support therefor so that the extent of the take-up action may be varied.

In the drawings Figure 1 is a front view showing more or less diagrammatically a portion of a sewing machine embodying the improvements.

Fig. 2 is a plan view of the looper, the thread controlling mechanism, and the operating devices therefor.

Fig. 3 is a view similar to Fig. 1, but show: ing the invention as applied to an overedge stitch forming mechanism wherein the thread of the under looper is controlled by the improved thread cont-roiler.

Fig. 4 is a plan view of the two loopers, the thread controller, and the operating mechanisms therefor.

The invention as shown in Figs. 1 and 2 is applied to a sewing machine including a needle 1 mounted for reciprocation in the usual manner. The bed plate of the machine is indicated at' 2 and the work support is indicated by the broken lines. The material is' held on the work support by a presser foot 3, and is fed across the work support by the usual feeding mechanism. Cooperating with the needle 1 beneath the work support is a thread carrying looper 4. Said thread carrying looper 4 is provided plate 2 of the machine.

with an eye 5' and a groove 6 along which the thread indicated at 7 passes to the eye of the looper. This looper is mounted in a looper carrier 8, which is pivoted at 9 to a support 10 which is oscillated in the usual manner for giving needle avoiding movements to the looper. The looper is oscillated by means of a link 11 connected to a ball stud 12 on the looper carrier, and also connected to a ball stud 13 carried by the 7 end of an arm 14 vwhich is fixed to a shaft 15 mounted for oscillation in suitable bearings carriedby the Attached to this shaft 15 is a yoke 16 carrying a ball stud 17 with which the lower end of an eccentric strap 18 makes engagement. This eccentric strap cooperates with an eccentric 19 on the main shaft 20.

The looper thread 7 passes through a thread guiding eye 21 carried by a plate 22. There is another thread guide 24 carried by this plate 22 and the plate 22 is adjustably mounted on a bracket 23 attached to the bed of the machine. The thread 7 passes first throughthe thread guide 21 and then through the thread guide 24. e

Mounted on the shaft 15 is an arm 25 -which extends upwardly. Attached to this arm 25 is the take-up member 26 which is in the form of two flat plates spaced from each other and secured to the arm 25 by a bolt 27 passing through a slot in the arm so that the plates 26, 26 may be raised and lowered on the arm 25. The plates 26 are so constructed that the outer faces thereof in the region 28 are substantially concentric to the axis of the shaft 15. The outer faces of these plates in the region 29 incline upwardly so as to provide a take-up shoulder termia counterclockwise direction for moving the looper to the forward end of its stroke. At

3 is pivoted at 38.

this time the link 11 and the arm 14 are substantially in alinement which gives a. dwell to the looper at the forward end of its stroke. When the shaft is moved in a clockwise direction the arm 14 is lifted and the looper is retracted. At this time a portion of the thread controlling plates 29 comes into engagem'ent with the thread passing through the thread uides 21 and 24. The thread will be bent and face 29 on the plates and will come in contact with the cast-off finger 31 which will gradually force the thread outwardly on this inclinedface 29 and finally strip it from said face so that it passes over the shoulder 29 onto the curved face 30. The parts are so timed that'when the looper is moving backward or being retracted the looper thread will be taken up and it will be cast off at a proper time so as to aid in the proper stitch formation and so as to give slackto the looper to move onto therear end of its stroke. When the thread is cast-off from this shoulder it will be retained by the curved face 30 which will gradually give the thread up as the looper moves forward into the next needle thread loop. The said finger 33 will strip the thread back off from this curved face 30 when the thread controller plates are moving -moves from the left toward the right as it enters the needle thread loop and the loop of thread formed by the looper is taken by the spreader or looper 36 and carriedovcr the work support and positioned for the needle to enter the same. The thread carrying looper is mounted on a carrier 37 which Said carrier has a rearwardly projecting arm connected to a link 39 which in turn is connected to an arm 40 fixed to asleeve 41, see Fig. 4, mounted for free oscillation on a shaft 42. Thesleeve is :provided with a yoke member 43 carrying a ball stud 44 with which an eccentric strap 45 makes engagement. This eccentric strap cooperates with an eccentric 46 on the main shaft 47. The overedge thread carrying looper 36 is mounted on a carrier 48., A link 49 is connected to the carrier at one end, and

at its other end is connected to an arm 50 fixed to the outer end of the shaft 42.

carried along with this inclined.

Mounted on this shaft 42 is a yoke 51 carrying a ball stud 52 with which an eccentric strap 53 makes engagement. This eccentric strap cooperates with an eccentric 54 on the I main shaft 47.

The thread for the looper 35 is indicated at 55. It passes through a tension.56 and then through the looper. This thread also passes through a thread guide 57 carried by a plate 58 and thence to a thread guide 59 carried by theplate, and said plate is mounted on a bracket 60. Mounted on the arm 50 is a thread controlling member 61. Said thread controlling member is in the form of two plates which are spaced from each other and these plates are so positioned that'they will move back and forth between the thread guides 57 and 59. This thread controlling member 61 is adjustably attached to the arm 50 by a clamping bolt 62 which passes through a slot in the arm. This permits the thread controlling member to be shifted toward and from the center or axis of the shaft. 42 for varying the extent of the take up of the looper thread.

Located between the plates forming the thread controlling member 61 is a cast off finger 63 and also a stop finger64. The plate carrying these fingers is mounted on the bracket 60. The thread controlling member 61 is provided with a curved face 64' leading to an inclined face 65 forming a shoulder which engages the thread passing through the thread guides when said thread controlling member 61 is oscillated toward the left, as viewed in Fig. 3. 'This takes up the looper thread and the finger 63 casts it off from the shoulder and it is retained on the curved face 66 of the thread controlling member. This curved face is substantially concentric with the axis of the shaft 42.

The thread controlling member 61 is carried by the operating mechanism for the overedge looper 36. When the overedge looper is retracted the under edge looper is also being retracted, and it is at this time that the shoulder on the thread controller 61 makes contact with the looper thread and takes up the slack formed in the looper thread due to the releasing of the. looper thread loop from the overedge looper. It is also retained as the looper moves onto the rear end of its stroke, and will be given up to the under looper so as to permit its free of whichmay be located beneath the work-..

support. By shifting the position of the thread controlling element outward or inward relative to the axis of the shaft which oscillates the same the extent to which the thread is taken up may be varied.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is

1. The combination of a thread carrying looper, a cross shaft, a main shaft, means operated by the main shaft for oscillating said cross shaft, means operated by the cross shaft for oscillating said looper, a thread controlling member oscillated by said cross shaft and having a shoulder for engaging and taking up the looper thread and a retaining surface associated therewith, spaced thread guides for directing the thread into the path of said shoulder, and a stripper finger for stripping the thread from said shoulder onto said retaining surface.

2. The combination of a thread carrying looper, a cross shaft, means operated by the cross shaft for oscillating said looper, a thread controlling member oscillated by said cross shaft and having a shoulder for engaging and taking up the looper thread and a retaining surface associated therewith, spaced thread guides for directing the thread into the path of said shoulder, a stripper finger for stripping the thread from said shoulder onto said retaining surface, and means whereby the position of said thread controlling member relative to the axis of said cross shaft may be shifted for varying the extent to which the thread is taken up.

3. The combination of a thread carrying looper mounted beneath the work support, a cross shaft mounted beneath the work support, an arm carried thereby, a link connecting said arm to the looper for oscillating the looper, a second arm carried by said cross shaft, a thread controlling member mounted on said second arm and having a shoulder adapted to engage and take up the thread and a retaining surface associated with said shoulder, thread guides for directing the looper thread into the path of said shoulder, and a stripper finger for engagingsaid thread and stripping the same from said shoulder onto said retaining surface.

4. The combination of a thread carrying looper, a cross shaft, a main shaft, means operated by the main shaft for oscillating said cross shaft, means operated by the cross shaft for oscillating said looper, a thread controlling member oscillated by said cross shaft and having a shoulder for engaging and taking up the looper thread and a retaining surface associated therewith, spaced thread guides for directing the thread into the path of said shoulder, a stripper finger for stripping the thread from said shoulder onto said retaining surface, and a stop finger asso ciated with said stripper finger for retaining and stripping the thread from the retaining surface on the thread controlling member.

5. The combination of a thread carrying looper mounted beneath the work support, a

cross shaft mounted beneath the work supv associated with the stripper finger and adapted to engage the thread and strip the same from the thread engaging surface onto the shoulder.

In testimony whereof, I aifix my signature.

FRIEDRICH LUTZ. 

